A Double‐Charged Organic Molecule Additive to Customize Electric Double Layer for Super‐Stable and Deep‐Rechargeable Zn Metal Pouch Batteries

Abstract

The electrochemical performance of aqueous zinc metal batteries (AZMBs) is highly dependent on the electric double layer (EDL) properties at Zn electrode/electrolyte interface. Herein, a novel reconfigured EDL is constructed via a double‐charged theanine (TN) additive for super‐stable and deep‐rechargeable AZMBs. Experiments and theoretical computations unravel that the positively charged TN not only serves as preferential anchor to form a water‐poor Helmholtz plane onto the Zn anode, but also its anionic end could coordinate with Zn2+ to tailor the solvation structure in the diffusion layer and further reconstruct the inner H‐bonds networks, thus effectively guiding uniform Zn deposition and suppressing the water‐induced side reactions. Consequently, the Zn//Zn cells acquire outstanding cycling stabilities of nearly 800 h at a high depth of discharge of 80%. Moreover, the Zn//VOX full cells deliver substantial capacity retention (94.12% after 1400 cycles at 2 A g−1) under practical conditions. Importantly, the designed 2.7 Ah Zn//VOX pouch cell harvests a recorded energy density of 42.3 Wh Kgcell−1 and 79.5 Wh Lcell–1, with a remarkable capacity retention of 85.93% after 220 cycles at 50 mA g−1. This innovative design concept to reshape the EDL chemistry would inject fresh vitality into developing advanced AZMBs and beyond.

Multifunctionalized Supramolecular Cyclodextrin Additives Boosting the Durability of Aqueous Zinc-Ion Batteries

“…According to the linear relationship between the scan rate and current density, the bilayer capacitance, as an important parameter to measure the state of the electrode surface, can be obtained, as shown in Figure 2c. 34 The bilayer capacitance in pure ZnSO 4 electrolyte is significantly higher than that in NMI-CDOTS/ZnSO 4 electrolyte, which can be explained by the preferential adsorption of NMI-CD + in the double layer structure of the Zn anode surface. The above results are consistent with the analysis of FTIR spectroscopy.…”

“…Cyclic voltammetry of Zn||Zn symmetric cells in ZnSO 4 and NMI-CDOTS/ZnSO 4 electrolyte was investigated at different scan rates in the voltage interval of −15 to 15 mV (Figure S6). According to the linear relationship between the scan rate and current density, the bilayer capacitance, as an important parameter to measure the state of the electrode surface, can be obtained, as shown in Figure c . The bilayer capacitance in pure ZnSO 4 electrolyte is significantly higher than that in NMI-CDOTS/ZnSO 4 electrolyte, which can be explained by the preferential adsorption of NMI-CD + in the double layer structure of the Zn anode surface.…”

Dynamic Molecular Interphases Regulated by Trace Dual Electrolyte Additives for Ultralong‐Lifespan and Dendrite‐Free Zinc Metal Anode

“…This is due to the formation of SL 2À molecular layer on metallic Zn surface to substantially suppress undesirable side reactions including electrode corrosion and HER. [63][64][65] Figure 3b shows the galvanostatic electrodeposition behaviors of metallic Zn in the ZS aqueous electrolyte with/without DM and SLS additives. Different from the ZS electrolyte, the ZS-DM-SLS hybrid electrolyte enables a low nucleation potential of ~1.3 mV and a low plateau potential of ~17.4 mV during the Zn electrodeposition.…”

Realizing High Reversible Zinc Metal Anode by Modulating Surface Chemistry and Crystal Structure

“…Current various modification strategies have been developed to regulate the Zn 2+ plating/stripping behavior at interface, [5] such as constructing artificial interface layers (e.g., ZnSe, [6] Bi, [7] polyamide, [8] TiO 2 , [9] and Zn 3 (OH) 2 V 2 O 7 •2H 2 O), [10] functionalized separator (e.g., composite separator [11] and ion-sieving separator), [12] and modifying electrolyte recipes (e.g., thiourea, [13] theanine, [14] and inorganic carbon nanomaterials). [15] For example, Wang et al [16] prepared a MOF-based ionic sieve inter phase on the surface of Zn metal for adjusting Zn 2+ ions flux toward dendrite-free Zn anode.…”